Yuan Jianda, Latouche Jean-Baptiste, Hodges Joanna, Houghton Alan N, Heller Glenn, Sadelain Michel, Riviere Isabelle, Young James W
Laboratory of Cellular Immunobiology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
J Immunol. 2006 Feb 15;176(4):2357-65. doi: 10.4049/jimmunol.176.4.2357.
Oncoretroviral vectors encoding either full-length Ag or a corresponding immunodominant peptide were expressed in Langerhans-type dendritic cells (LCs) differentiated from CD34(+) progenitors. We used human CMV as a model Ag restricted by HLA-A*0201 to define parameters for eventual expression of cancer Ags by LCs for active immunization against tumors. Stimulation by CMVpp65(495-503)-pulsed LCs, CMVpp65(495-503)-transduced LCs, and full-length CMVpp65-transduced LCs respectively increased tetramer-reactive T cells with an effector memory phenotype by 10 +/- 11, 34 +/- 21, and 51 +/- 24-fold (p < 0.05) from CMV-seropositive donors. CMV-specific CD8(+) CTLs achieved respective frequencies of 231 +/- 102, 583 +/- 219, and 714 +/- 281 spot-forming cells per 10(5) input cells (p < 0.01) in ELISPOT assays for IFN-gamma secretion. LCs expressing full-length Ag stimulated greater lytic activity than either peptide-transduced or peptide-pulsed LCs (p < 0.05), all in the absence of exogenous cytokines. pp65-transduced LCs presenting class I and II MHC-restricted epitopes expanded IFN-gamma-secreting CD4(+) T cells, whereas pp65(495-503)-transduced LCs did not. CD4(+) T cell numbers even declined after stimulation by pp65(495-503) peptide-pulsed LCs. CD4(+) T cell depletion confirmed their contribution to the more robust CTL responses. LCs, transduced with a retroviral vector encoding full-length Ag, stimulate potent CTLs directed against multiple epitopes in a CD4(+) Th cell-dependent manner.
编码全长抗原（Ag）或相应免疫显性肽的嗜肝性逆转录病毒载体在由CD34(+)祖细胞分化而来的朗格汉斯型树突状细胞（LCs）中表达。我们将人巨细胞病毒（CMV）作为受HLA - A*0201限制的模型抗原，以确定LCs最终表达癌症抗原用于主动免疫治疗肿瘤的参数。分别用CMVpp65(495 - 503)脉冲处理的LCs、CMVpp65(495 - 503)转导的LCs和全长CMVpp65转导的LCs刺激后，来自CMV血清阳性供体的具有效应记忆表型的四聚体反应性T细胞分别增加了10±11、34±21和51±24倍（p<0.05）。在用于检测γ干扰素分泌的ELISPOT分析中，CMV特异性CD8(+)CTLs在每10(5)个输入细胞中分别达到了231±102、583±219和714±281个斑点形成细胞的频率（p<0.01）。在没有外源性细胞因子的情况下，表达全长抗原的LCs比肽转导或肽脉冲处理的LCs刺激产生了更强的裂解活性（p<0.05）。呈现I类和II类MHC限制性表位的pp65转导的LCs可扩增分泌γ干扰素的CD4(+)T细胞，而pp65(495 - 503)转导的LCs则不能。用pp65(495 - 503)肽脉冲处理的LCs刺激后，CD4(+)T细胞数量甚至下降。CD4(+)T细胞耗竭证实了它们对更强有力的CTL反应的贡献。用编码全长抗原的逆转录病毒载体转导的LCs以CD4(+)辅助性T细胞依赖的方式刺激针对多个表位的强效CTLs。
